Fire extinguishing apparatus



Feb. 20, 1968 J. E. FOGELGREN 3, 9

FIRE EXTINGUISHING APPARATUS Filed March 18, 1966 6 Sheets-Sheet lINVENTOR J 0 IVA/E E651 GPE V ATTORNEYS 1968 .J. E. FOGELGREN 3,369,609

FIRE EXTINGUISHING APPARATUS Filed March 18, 1966 6 Sheets-$heet 2INVENTOR Jaw/v5 P06616186 Feb. 20, 1968 J. E. FOGELGREN FIREEXTINGUISHING APPARATUS 6 Sheets-Sheet 5 Filed March 18, 1966 fi/VEE6152 GEE/Y Feb. 20, 1958 J, v FOGELGREN 3,369,609

FIRE EXTINGUISHING APPARATUS Filed March 18, 1966 6 Sheets-Sheet 4ATTORNEYS 1968 .1. E. FOGELGREN 3,369,609

FIRE EXTINGUISHING APPARATUS Filed March 18, 1966 6 Sheets-Sheet 5 INVEN TOR. F2654 war/v Feb. 20, 1968 J. E. FOGELGREN 3,369,609

FIRE EXTINGUISHING APPARATUS Filed March 18, 1966 6 Sheets-Sheet 6INVENTOR.

Ja/M/E', Ffoaax sway i I? .77 0/94 6 Y3 3,369,609 FIRE EXTINGUISHINGAPPARATUS .Iohn E. Fogelgren, Rockville, Md, assignor to G-L Industries,Westville, N.J., a corporation of New Jersey Continuation-impart ofapplication Ser. No. 446,887, Apr. 9, 1965. This application Mar. 18,1966, Ser. No. 543,465

16 Claims. (Cl. 169-31) This invention relates to a projectile fireextinguishing grenade and a gun for accurately projecting the same.

This application is a continuation in part of application Ser. No.446,887, filed Apr. 9, 1965, now abandoned.

In many instances of fighting fires, it is desired that the firemanremain a safe distance from the fire while accurately distributing afireextinguishing material upon States Patent the 'fire. Such instancesinclude fighting fires in hazardous storage areas (containingexplosives, chemicals or highly inflammable materials), boats and otherdangerous or inaccessible areas and gasoline and oil spill fires. It hasalso been desired to place a fire-extinguishing material upon a firewhich is located behind drywall walls or ceilings, panelled doors, orwindows. Water and most other liquids have been unacceptable forextinguishing such fires as gasoline fires and electrical fires. Freeflowing fire extinguishing chemicals, such as potassium bicarbonate, canbe used on almost any type of fire. However, until the presentinvention, no means were known for accurately directing free flowingfire extenguishing chemicals upon large fires from a safe distance, forinstance, over 50 feet away, in sufiicient volume to extinguish orseriously retard the fires, or to direct fire extinguishing chemicalsupon fires behind drywall walls and ceilings or panelled doors.

It is an object of this invention to provide a compressed gas-operateddevice to project free flowing fire extinguishing chemical grenades uponfires from a safe distance with rapidity and accuracy.

It is an additional object of this invention to provide a device whichuses differential piston areas exposed to fluid pressure for both thetriggering or valve operation and the propelling of a fire extinguishingprojectile.

It is another object of this invention to provide a compressedgas-operated device to project grenades, or containers, from one pointto a second, predetermined point, which may be appreciable distance fromthe first point, with rapidity and accuracy.

It is a further object of this invention to provide a free flowing fireextinguishing chemical grenade with a gasoperated time delay fuse. Stillfurther objectives and the entire scope of applicability of the presentinvention will become apparent from the detailed description givenhereinafter; it should be understood, however, that the detaileddescription, while indicating preferred embodiments of the invention, isgiven by way of illustration only, since various changes ormodifications within the scope of the invention will become apparent tothose skilled in the art from this detailed description.

Briefly, the invention in part consists of a gun which contains twocompressed gas chambers. Operation of a trigger releases the gaspressure in the rear chamber which causes differential piston areasexposed to the front chamber gas pressure to operate valves whichrelease the compressed gas in the front chamber and direct the releasedgas upon the rear face of a grenade contained within the tube of the gunto propel the grenade from the gun toward a fire or other target. At thesame time that the valves are operated, the valve stem delivers animpact to an arming device on the grenade. The invention also consistsof an associated grenade which contains free flownig fire extinguishingchemicals and a compressed gas cartridge which operates a time delayfuse. The impact from the guns valve stem causes a plunger to puncturethe gas cartridge. The compressed gas operates a time delay fuse devicewhich, after a predetermined period of time, releases the contained gasto the inside of the grenade. The sudden gas pressure thus releasedcauses the grenade casting to split, dispersing the fire extinguishingpowder charge in a cloud which blankets the target area.

The invention will be more clearly understood from the drawings, inwhich:

FIGURE 1 is a view of the compressed-gas operated, fire extinguishinggrenade projecting gun;

FIGURE 2 is a side view, partly in section, of the gun of FIGURE 1;

FIGURE 3 is a sectional view of the gun of FIGURE 2, taken along lines33;

FIGURE 4 is a view of an embodiment of the gun of FIGURE 1, where afour-tube magazine is provided on the gun;

FIGURE 5 is a side view, partly in section, of the gun of FIGURE 4,showing the magazine rotator;

FIGURE 6 is a sectional view of the gun of FIGURE I 5, taken along lines6-6;

FIGURE 7 is a side view in section of the fire extinguishing grenade;

FIGURE 8 is a partial section of the grenade of FIG- URE 7, showing amodification of the time fuse;

FIGURE 9 is a side view, partly in section, of the grenade of FIGURE 7,modified for hand arming and throwing;

FIGURE 10 is a side view, partly in section, of an embodiment of the gunof FIGURE 2, wherein the valve and valve seat have been modified and avalve guide is used;

FIGURE 11 is a sectional view of the valve and valve guide of FIGURE 10;

FIGURE 12 is an end view of the valve guide of FIG- URE 10;

FIGURE 13 is a side view in section of the grenade of FIGURE 7, showinga modification of the time fuse;

FIGURE 14 is a side view in section of the grenade of FIGURE 7, showingyet another modification of the time fuse;

FIGURE 15 is a sectional view of the rear piston 141 of FIGURE 14, takenalong line 1515;

FIGURE 16 is a sectional view of the front piston 140 of FIGURE 14,taken along line 16-16; and

FIGURE 17 is a side view in section of the grenade of FIGURE 14, showingan additional embodiment of the modified time fuse and also amodification of the arming mechanism.

In FIGURE 1, the gun consists of a stock assembly 101, a rear receiver102, a front receiver 103, pressure chamber tube 104, a barrel 105, afront handle 106, a rzar handle 107, a trigger 108 and an air t-ubecoupling 1 9.

In FIGURE 2, the propelling means of gun 200 consists of two chambers102 and 202 which may contain pressurized gas. These two chambers areseparated by wall 203 and connected by one-way ball check valve 204located in wall 203' Running through chambers 201 and 202 and wall 203is valve stem 205. The front of valve stem 205 is attached to frontvalve 206 while the rear of the valve stem is connected to rear valve207. When closed, front valve 206 seats on seat 208, which is part offront receiver 103. Extending forward of front receiver 103 is barrel105, which is shown holding a grenade 211. The front of front valve 206carries a rod-like extension 212, so arranged that it strikes the rearof grenade 211 when the gun is fired. Attached to the bottom of frontreceiver 103 is front grip 106.

The front pressure chamber 201 is defined by front valve 206 and valveseat 208, pressure chamber tube wall 104 and wall 203.

Wall 203 is part of rear receiver 102. Wall 203,. rear receiver 102 andrear valve 207 define rear chamber 202. Spring 216 which seats in arecess in Wall 203 is biased to exert a pressure on valve 207 to keepvalve 207 seated on valve seat 237 except when the gun is fired. Asleeve 245 on the part of rear wall 203 extending forward'of' the recessserves as a support and guide for valve stem 205. Valve seat 237 is partof rear housing .218. This a housing is held in place on receiver215 byretaining ring 219, and is sealed by O-ring 220.

The chamber 221 defined by rear valve 207 and 'housing 218 is 'open tothe atmosphere through ports (better seen in FIGURE 3) in housing 218.Housing 218 also contains a sleeve portion 222 in which a rearwardrodlike extension 242 of valve 207 rides. This sleeve 222 is fitted witha safety lock assembly 238. Stock assembly 101 is fitted to sleeve 222.

Port 223 is contained in rear receiver 102 and opens into rear pressurechamber 202. Balanced spool valve 224 is located in port 240 betweenport 223 and tube 225, which connects to a source of compressed gas (notshown) by quick-disconnectcoupling 109. Tube 225 is enclosed by reargrip 107.

Balanced spool valve 224 consists of a spool and associated O-rings 228,229, and 230. These three O-rings must be approximately the same size.The portion 231 of the spool between O-rings 229 and 230 is of reduceddiameter. The rear portion 235 of port 240 is of enlarged diameter andopens to the atmosphere. The front of spool valve 224 is connected totrigger 108, which is protected by trigger guard 233.

When the trigger 108 is at its rearmost or firing position, asillustrated in FIGURE 2, the flow of air from tube 225 is blocked byportion 234 of the spool valve 224. This. portion 234 is sealed byO-rings 228 and 229. At the same time, port 223 can discharge around thereduced area 231 'of the spool, which area is open to the atmosphere asO-ring 230 is smaller than the diameter of the enlarged portion 235 ofport 240.

When the trigger 108 is at the mid-point of its horizontal movement, theflow of gas from tube 225 is still blocked by O-rings 228 and 229.O-ring 230 is engaged with the interior surface of port 240 at the areadesignated 236, and, together with O-ring 229, blocks the discharge ofgas from port 223.

When the trigger 108 is at its forward or charging position, O-ring 229has moved past the entrance of tube 225 while O-ring .230 is still inthe area 236 to seal the contained gas from the atmosphere. Gas can thenpass through tube .225, through the space between spool portion 231 andthe wall of port 240, and into rear chamber 202 through port 223.

As previously mentioned, the O-rings 228, 229 and 230 are of equal size.Since they are of such equal size, gas contained between any two of therings exerts an equal pressure on each ring. Since the pressures areequal, spool valve 24, is not biased in either direction in which itcould travel and consequently is termed a balanced valve.

It is essential for the operation of the present invention that thefront valve 206 have a smaller surface area exposed to internal gaseouspressure than rear valve 207 and preferably front valve 206 is ofsignificantly smaller exposed surface area. This requirement can readilybe appreciated from the following description of the operation of thegun.

In the charging operation, when the coupling 109 is connected to asource of compressed gas and an associated regulator, set, for example,to deliver 150 psi. air, and the trigger 108 is pushed all the wayforward, gas flows from the source, through the regulator, through tube225, and through the space between the reduced portion 231 of the spool224 and the interior wall of port 240. While flowing around the spoolarea 231, the

4, gas is sealed against escape by O-rings 230 and 229. The

gas then passes into rear pressure chamber 202 by way ofport 223. Valve207, which is lightly held in positionon valve seat 237 by spring 216,is firmly seated on the seat by the gas pressure exerted on its face. Atthe same time, ball 241 in one-way ball check valve 204 is pushedforward, allowing the gas to pass into forward pressure chamber 201.Front valve 206 is seated on front valve seat 208 by the force exertedon rear valve 207 and transmitted by valve stem 205. The gas presure infront chamber 201 builds up until it is equal to the pressure in rearchamber 202. Because rear valve 207 has a greater surface area exposedto the gas pressure than front valve 206, and because the pressures inthe two chambers are equal, the valves are held firmly shut by the gaspressure operating on the differential areas to produce a resultantforce tending to move the whole valve assembly to the rear.

In firing the gun, the trigger is pulled to its rearmost position. Spoolvalve section 234, with associated O-rings 228and 229, blocks thepassage of gas flow from tube 225. Since O-ring 230 has been moved intothe enlarged area 235 of port 240, port 223 can, discharge the gasinrear chamber 202 to the atmosphere. As the pressure in rear chamber 202drops, ball 241 in one-way ball check valve 204 is moved to its rearwardposition, blocking flow from chamber 201 to chamber 202. Thus frontpressure chamber 201 retains its charged pressure, for example, psi.pressure, While rear pressure chamber 202 is discharging gas to theatmosphere and dropping in pressure. As rear chamber 202 loses itspressure, the point is reached where the total force (pressure timesarea) exerted pushing valve 206 forward is greater than the force whichpushes valve 207 rearward. At that time the valve system (front valve206, valve stem 205, and rear valve 207) moves forward. As soon as rearvalve 207 is clear of rear valve seat 237, the gas remaining in rearchamber valves and slams the valve system forward. The gas con tained infront pressure chamber 201 then rushes past valve seat 208 and exhauststhrough muzzle 105, propelling grenade 211 to the target. The valvesystem initially is moving faster than the grenade 211 and the frontrod-like extension 212 strikes a plunger in the base of grenade 211. Aswill be explained, this blow starts the time-delay fuse in the grenadeinto operation.

The one-way ball check valve 204 may be replaced with any equivalentpositive one-way flow regulator. However, the ball check valve ispreferred as it gives more reliable performance than equivalents such asflap valves.

FIGURE 3 is a cross-section of the gun 200'taken along line 3-3whichpasses through the safety lock assembly. Rear receiver 102surrounds rear housing 218. Ports 301 pass through rear housing 218.Rear housing 218 has a sleeve portion 222 extending to its rear. Thesleeve portion 222 is fitted with a safety lock assembly 238 which locksextension 242 of the rear valve. The safety lock assembly consists of alocking pin 302 which contains grooves 303 and 304. Spring-biased detent307 is held in bore 306'.

When the locking pin is pushed to the left as far as it will travel (asillustrated in FIGURE 3), detent 307 engages groove 303 to hold pin 302in place. The enlarged portion 308 of thepin engages a groove cut intothe extension 242 of therear valve, and so locks the extension.

When the locking pin is pushed to the right, detent 307 engages groove304 and holds the pin in position. The reduced portion 309 of the pin isthen over the groove cut into the extension 242 of the rear valve butdoes not cugage it and the gun may be fired.

A modification of front valve 206 is shown in FIG- URE 10. Front valveseat 2008 has a tapered seating surface. Front valve 2006 is alsotapered. By using tapered valves and valve seats, the front valve openseasier, seats in a more positive manner, and allows a reduction in theforce exerted by spring 216.

Valve guide 1001 is firmly attached by means of bolts 1002 to the backof front valve 2006. This valve guide 1001 reduces whip in valve stem205. Valve guide 1001 rides on the innermost portion of front valve seat2008, thereby reducing vibration and whip of front valve 2006 when thevalve is unseated. Extension 2012 is attached to the front end of valvestem 205. This extension 2012, which functions in the same manner asrod-like extension 212 of FIGURE 2, strikes the rear of a grenadecontained within barrel 105 when the gun is fired.

FIGURE 11 is a side view in section of valve 2006 and valve guide 1001,which are attached by means of bolts 1002. Valve guide 1001 has 4 ribs112 and an annular ring 114. Valve guide 1001 contains an inner bore 111which may be essentially the same diameter as valve stem 205 or may beof larger diameter as shown.

FIGURE 12 is an end view of the valve guide 1001 of FIGURES l and 11.This valve guide 1001 has 4 ribs 112, an annular ring 114 and 2 bores120, for receiving the bolts 1002 of FIGURES l0 and 11.

While it is readily appreciated that many various materials may be usedin the manufacture of the various parts of the gun, plastics, and inparticular high impact polyethylene and ABS, because of their highstrength and low weight, have proved particularly desirable.

Since it has been found desirable to place as many fire extinguishinggrenades on a fire in as short of a time period as possible, thepreferred embodiment of the fire extinguishing grenade gun is shown inFIGURE 4 as gun 400. The gun of FIGURE 1 has been modified by theinclusion of a 4-tube magazine 401.

FIGURE 5 is a side view of the magazine gun 400, shown partly insection. Four tubes 501 are mounted on tube receiver 502. Sleeve 503 isalso mounted on tube receiver 502 in bore 504 and is located parallel toand central of the tubes 501. The magazine (consisting of the four tubes501, tube receiver 502, and sleeve 503) is mounted on the gun by meansof spindle 505.

Housing 506 is mounted on front receiver 103 of the gun. Housing 506 issplit into several parts for ease of assembly of the magazine rotator,and the parts are bolted together. Bearing 507 and flanged bearing 508support spindle 505 and allow it to rotate freely in the housing. Locknut and washer 510 hold spindle 505 in housing 506. Plunger 509 isfreely, axially mounted in spindle 505 and has cap 511 mounted on itsrear end. Spring 5112 biases cap 511 to the rear. Two spindle latches513 are pivotally mounted on the front end of spindle 505 by pins 514.The spindle latches 513 have fingers 515 which ride in a groove 5116 cutinto the end of the plunger. The spindle is keyed by means of pin 517(shown dashed) to tube receiver 502. Ratchet 518, which is more clearlyseen in FIGURE 6, is keyed by key 519 to spindle 505. Ball plunger 520acts as a detent for ratchet 518.

U-shaped gasket 521 seals the gap between the front receiver and thetube receiver 502. The gas pressure in the firing operation of the guncauses the front face of gasket 521 to firmly engage the tube receiverand seal the gap between the gun and the magazine.

The magazine and spindle assembly shown permit rapid interchange ofmagazines on the gun. Spinde latches 513 and spindle 505 easily slipinto bore 504 and sleeve 503. When fully inserted, the spindle latches513 open and engage the front end of sleeve 503. Spring 512 pushesplunger 509 toward the rear and the groove 516 in the plunger pullsspindle latch fingers 515 rearward with it. As the spindle latch fingersmove rearward, spindle latches 513 pivot about pins 514 to throw therear ends of the spindle latches outward to engage sleeve 503 (as shownin FIGURE 5). The magazine is then held firmly on the gun. When cap 511is pushed forward, the rear shoulder of groove 516 in plunger 509 pushesthe spindle latch fingers 515 forward, and thus causes the rear ends ofthe spindle latches to move inward and disengage sleeve 503. Themagazine assembly 401 is then free to slip off of the spindle 505 and beremoved from the gun.

FIGURE 6 is a cross-section of the rotator assembly of FIGURE 5, takenalong lines 6-6. Port 601 in housing 506 connects front pressure chamber201 and a channel (not shown) in gasket 602 which is held on housing 506by cover plate 603. The channel opens into the area between cover plate603 and piston 604. Piston 604 is located in bore 605 in housing 506,and seals against the walls of bore 605 by means of O-ring 606.Connecting rod holder 607 fits into piston 604. Spring 608 biasesconnecting rod holder 607 and piston 604 toward cover plate 603.

Connecting rod 609 is held by connecting rod holder 607 inside of spring608fThis connecting rod is shown in FIGURE 6 in the position it would bein when the gun has been fired. The connecting rod is also shown dashedin FIGURE 6 in the position it would be in when the gun has beencharged.

In operation, piston 604 is held by spring 608 against gasket 602 whenthe gun is uncharged. Spring 608 also holds connecting rod holder 607against piston 604. Connecting rod 609 is attached to connecting rodholder 607 and travels toward cover 603 along with piston 604 andconnecting rod holder 607. Since connecting rod 609 is spring loaded, ithas a tendency to drop down toward front receiver 103. Magazine 401 isthen free to rotate, along with spindle 505 and ratchet 518, held onlyby ball plunger detent 520.

When the front pressure chamber 201 is charged with compressed gas, asmall portion of the gas passes through port 601 and the channel ingasket 602 to the area between the gasket and the face of piston 604.The force exerted on the piston face pushes the piston, connecting rodholder 607 and connecting rod 609 against the spring 608 and toward theratchet 518. The end of the connecting rod 609 engages one of the fourfingers of ratchet 518 and. rotates the ratchet (and with it, thespindle and the magazine assembly). The ratchet is rotated by theconnecting rod until the connecting rod is in the dashed position ofFIGURE 6. The gas pressure exerted upon piston 604- holds the connectingrod firmly in the dashed position, locking the ratchet against rotation.When the gun is fired, spring 608 returns the piston, the connecting rodholder, and the connecting rod to their original position as shown inFIGURE 6.

While at the present time it is contemplated that the compressed gasused in the gun will be under a pressure of less than 1000 p.s.i. (afterpassing through a pressure regulator, if such be necessary), no maximumpressure limitation upon the gun of this invention is contemplated.Parts may be made thicker, or of stronger materials, to handle anypractical pressure. However, the preferred pressure range is 50-500p.s.i.g.

In FIGURE 7, the grenade 700 is enclosed by a case 701, preferably madefrom rotationally moldable, fusable polyethylene powder, such asMicrothene produced by US. Industries, Inc. Fuse housing 702 closes therear of case 701 and is heat welded to the case. Lip 703 is molded ontothe case 701 to retain the grenade in the barrel of the gun. Lip 703fits into a groove in the rear of the barrel of the gun and is shearedoff when the grenade is fired.

A cartridge 704 containing a compressed gas, for example, carbon dioxideor nitrogen, is fitted to the front of fuse housing 702, with the area705 of the cartridge, designed for release of the contents of thecartridge upon puncture, facing the rear of the grenade. Inserted inaxial bore 709 located in fuse housing 704 is a plunger 706 comprising apointed end 707, a groove containing an O-ring 708,21 shoulder portion710 and a reduced diameter portion 711. Plug 712 is located at the endof chamber 713 and serves as a guide for the reduced diameter portion711 of plunger 706. The plug 712 has a recessed portion 714 in its outersurface. When the grenade is in a loaded, unfired condition, the end ofthe plunger 706 protrudes. from the recess 714 and is approximatelyflush with the outer face of plug 712.

Piston 715 is located on the portion 711 of plunger 706. The outerdiameter of piston 715 is slightly larger than the diameter of thechamber 713, insuring a tight fit. The front face of the piston 715 isbeveled to allow a measure of flexibility in the portion of the pistonwhich contacts the walls of chamber 713. The piston 715 has an innerbore which fits tightly over the reduced diameter portion 711 of plunger706 but is smallerthan shoulder 7100f the plunger. The piston 715 has asmall port 716 extending through it. As will be readily seen whenreading the descripition of the operation of the grenade time fuse, thediameter of this port will vary with the viscosity of the fluid employedin the fuse and with the time delay desired. Ports 717 connect the innerend of chamber 713 with the chamber 718 formed by case 701.

Chamber 718 is filled with a free flowing fire extinguishing chemical,such as Foray or Purple K, both dry powder fire extinguishing chemicalsproduced by Ansul Chemical Co. The chamber 713 between the plug 712andthe piston 715 is filled with a fluid, preferably an incompressible,viscous silicone grease, such as Dow Corning #4. When the grenade isloaded, the piston 715 is placed as far forward on the plunger 706 aspossible.

In operation, the cartridge 700 is loaded into a gun, such asrepresented by the numeral 200 inFIGURE 2, by sliding the grenade intothe end of the barrel of the gun and down the barrel until hp 703catches in its corresponding groove in the barrel to lock the grenade inthe barrel for carrying purposes. When the gun is fired, the projection212 on front valve 206 strikes the protruding end of plunger 706,causing the pointed end 707 of the plunger to puncture the area 705 ofcylinder 704. At the same time, the gas held under pressure in frontchamber 201 of the gun 200 is released through front valve 206,propelling the grenade from the barrel and toward the target.

When the area 705 of cylinder 704 is punctured, the contained gas exertsa force upon the pointed end 707 of plunger 706 tending to force theplunger rearward. O-n'ng 708 seals the gas in bore 709 as the plunger706 is moved rearward. Shoulder portion 710 of plunger 706 engagespiston 715 and the force tending to move the piston 706 rearward istransmitted to piston 715; AS piston 715 attempts to move rearwardagainst the con-- tained fluid which fills chamber 713, the force istransmitted to the fluid and forces the fluid through port 716. The rateof flow of the fluid thus metered through port 716 depends upon suchvariables as the viscosity of the fluid, the diameter of the port 716,and the force applied to the fiuid. The rate of flow of the fluid, andconse quently the rate of travel rearward of piston 715, may be changedby varying any of these variables, preferably the diameter of port 716.The diameter of port 716 is so adjusted that, for a givenfluidviscosity, fuse assembly, and gas pressure, the time required fromthe puncturing of the cylinder 704 to the time that O-ring 708 passesfrom bore 709 into chamber 713 is the desired fuse delay time.

When the O-ring 708 does pass from bore 709 into chamber 713, the gaswhich was contained in cartridge 704 is free to pass through port 717into the interior of case 701. The gas in the cylinder 704 is generallyunder quite high pressures, for example, about 900 p.s.i., and expandsso rapidly into the interior of case 701 so as to cause a shock thatsplits the case open. The free flowing fire extinguishing chemical whichhad been contained in case 701 is entrained by the gas and distributedover the area outside the case. For example, when ,a dry powder fireextinguishing powder, such as Foray, is used, the gas will distributethe powder over a circle 5 to 8 feet in radius around the grenade.

While most fluids may be used in thetirne fuse as sembly, it ispreferably a liquid which is incompressible and viscous, although gasesmay be used. Silicone greases have proved to be particularly desirable.They will not freeze under normal winter conditions and have a highviscosity. This high viscosity minimizesthe sealing problem and allowsthe port 516 in piston 515 to be large and therefore of not so criticala tolerance in manufacture.

The case of the grenade, when made of polyethylene, is

fuse, a grenade may be firedthrough a wall or door, on

the other side of which there is a tire, and have the time fuse operateat such a time as to deposit the free flowing fire extinguishingchemical upon the fire.

An alternative time fuse assembly 800 for the fire extinguishing grenadeis shown in FIGURE 8. Pressurized gas cartridge 704 is fitted to therear of fuse housing 801,

with the easily punctured area 705 of the cartridge facing the rear ofthe grenade. Plunger 802 is inserted in axial bore 803 of the fusehousing, and pointed end 807 is so arranged to puncture area 705 of thegas cartridge when the protruding end of the plunger is struck. Shoulder804 in bore 803 engages shoulder 805 on the plunger to keep the plungerfrom being forced out of the rear of the bore when the gas cylinder ispunctured. If necessary, a gasket or O-ring may be inserted to fitbetween and seal the area between the two shoulders when they are forcedtogether.

Bore 806 leads from bore 803 to pressure chamber 807, located inenlarged portion808 of fuse housing 801.'Pressure chamber 807 isconnected to, the interior of the grenade by bore 809. Large piston 810separatespressure chamber 807 and secondary pressure chamber 811, whichare connected by small bore812. Stop 813 keeps the rear face of piston810 a minimal distance from the rear wall of secondary pressure chamber811..

Large piston 810 is connected by stem 814 to small piston 815, locatedin bore 809. O-rings 816 and 817 seal the outer surfaces of pistons 810and 815, respectively. As will be appreciated from a description of theoperation of the time fuse, small piston 815 must have a crosssectionalarea considerably smaller than that of large piston 810.

In operation, the rear end ofplunger 802 is struck by the front valverod-like extension when the fire-extinguish: ing gun is fired. This blowcauses the pointed end of the plunger to puncture the area 705 of gascylinder 704. The pressure of the gas thus released pushes the plungerrearward until it is stopped by the meeting of shoulders 804 and 805.

The gas passes through port 806 into pressure chamber 807. Since thecross-sectional area of large piston 810 is larger than that of smallpiston 815, the gas exerts a force tending to keep large piston 810pressing against stop 813. As the small port 812 is open, the gas leaksfrom pressure chamber 807 into secondary pressure chamber 811. When thepressures in the two chambers are about equal, the forces exerted by thegas in secondary pressure chamber 811 upon large piston 810 and by thegas in pressure chamber 807 upon small piston 815, which tend to movethe piston assembly (810, 814 and 815) forward, are greater than theforce exerted by the gas in pressure chamher 807 upon large piston 310,which tends to move the piston assembly to the rear, and consequentlythe entire 9 piston assembly moves forward, When O-ring 817 clears theouter end of bore 809, the gas in the fuse assembly is released to theinside of the grenade, and the sudden shock of the released gas splitsthe grenade casing.

The diameter of bore 812 is varied to produce different metering ratesof the gas passing from chamber 807 to chamber 811. By varying the rateof the gas flow through bore 812, the time from the instant the gascylinder is punctured until the time the gas pressure in chamber 811 hasbuilt up to the point where the piston assembly moves forward can beregulated.

A third time fuse assembly 130 for the fire extinguishing grenade isshown in FIGURE 13. An advantage of this particular fuse assembly isthat the fuse time may be varied after the completed grenade isassembled. The

\ time fuse assembly shown in FIGURES 7 and 8 are not adjustable and thefuse time will essentially be that selected at the time of the assemblyof the grenade, with possible variations due to temperature changescausing a resultant change in the fluid viscosity or the compressed gaspressure.

Fuse assembly 130 is illustrated as molded to the rear end portion ofthe grenade. This rear end portion is solvent welded at the rea 137 tothe grenade case 701. Plug 135 allows the grenade to be filled with thefire extinguishing chemical after the time fuse assembly 130 is attachedto the grenade case 701. The time fuse assembly 130 contains a plunger706 Which is similar to the plunger of FIGURE 7, except that threads 131are on the rear portion of the reduced diameter portion 711. Adjustabletiming nut 132 is screwed upon the reduced diameter portion 711. Sleeve134, which comprises the outer walls of chamber 713, has an annular web133 which is in tight, sliding contact with adjustable timing nut 132.Ports 136 are located in the body of fuse assembly 130.

In operation, firing the grenadeprojecting gun of the present inventiondelivers a sharp blow to plunger 706, causing pointed end 707 topuncture area 705 of cartridge 704. The compressed gas in cartridge 704pushes against the pointed end 707 of plunger 706, which is sealed byO-ring 70S. Shoulder portion 710 of plunger 706 engages piston 715 andthe force tending to move the piston 706 rearward is transmitted topiston 715. Chamber 713 is filled with an incompressible fluid, such asa viscous silicone grease, and as piston 715 attempts to move rearward,the force is transmitted to the fluid and forces the fluid through port716. As the plunger 706 moves rearward, it carries with its adjustabletiming nut 132. When the plunger 706 moves far enough back, ad justabletime nut 132 moves out of tight sliding contact with annular web 133.When this sliding contact is lost, the fluid contained within chamber713 is allowed to escape, thereby leaving essentially no resistance tothe rearward motion of plunger 706, Plunger 706 is therefore slammedrearward until O-ring 708 passes out of contact with bore 709 andreleases the compressed gas from cylinder 704 to flow through port 136and into the interior of the grenade.

One problem existing with the time fuses described above is the factthat temperature changes will cause a change in the pressure of the gascontained in cartridge 704, thereby changing the force (pressure timesarea) exerted upon the front face of plunger 706, which causes acorresponding change in the fuse time. The fuse of FIG- URE 13 may beadjusted to correct this temperature fuse time change, but suchadjustment is necessarily time consuming and inexact.

The time fuse embodiment illustrated in FIGURE 14 produces a constant,predetermined fuse delay time over wide temperature variance, i.e., forexample, to 90 F. Mounted upon the reduced diameter portion 711 ofplunger 706 are two pistons 140, 141 and spring 142. The chamber 713,which is similar to the correspondingly numbered chamber of FIGURE 7, isfilled with an incompressible fluid, for example, a silicone grease.Front piston 140 contains a sealing lip 143 which maintains close,liquid tight contact with the walls of chamber 713. A number of bosses144, which may, for example, be of circular cross-section, are mountedupon the rear face of piston 140. A number of ports 145 extend throughthe piston 140, each port 145 being centrally located in a boss 144. Asshown, spring 142 is mounted between the two pistons, 140, 141 andaround plunger 706.

Rear piston 141 has a sealing lip 146 riding in close, sliding contactwith the walls of chamber 713. The front face of piston 141 isrelatively flat, preferably at right angles to plunger 706, and capableof meeting with the rear faces of bosses 144. Port 147 extends throughpiston- 141. Port 147 should not be in line with any of ports 145, andport 147 should not be covered by a rear edge of a boss 144 when thepistons 140, 141 contact each other. Chamber 148 is defined by the wallsof the fuse housing and pistons 140, 141. Both piston 140 and 141 aremounted upon plunger 706, in liquid-tight, sliding contact thereupon.

The spring 142 is so chosen that the force to deform it is equivalent tothe force applied to the front face of piston 706 at the lowestcontemplated or design operating temperature. The port size is chosensuch that the desired fuse delay time will be achieved at thepredetermined, lowest contemplated operating temperature. As mentioned,a large number of ports 145 extend through a corresponding number ofbosses in front piston 140. The size of bores 145 is not critical, butthey are chosen of such a number and size as to be of much greatercrosssectional area than bore 147, e.g. the total cross-sectional areaof ports 145 may be 5, 10, or even 20 times the cross-sectional area ofport 147.

In operation, the time delay fuse of FIGURE 14 produces a constant fusedelay time over a wide temperature range. At the predetermined, lowestcontemplated temperature, for which spring 142 and port 147 weredesigned, the effect of front piston 140 will be small or negligible.The force exerted upon the front face of plunger 706 by the gasesreleased from cylinder 704 is transmitted to front piston 140 byshoulder 710 of the plunger 706. This force is in turn transmitted torear piston 141 by spring 142, the whole piston assembly consequentlyhaving a tendency to move in the rearward direction. Chamber 713 isfilled with an incompressible liquid. As rear piston 141 attempts tomove rearward, the force from the gas pressure on plunger 706 and thepistons 140, 141 is transmitted to the incompressible liquid, therebymetering the liquid through port 147. Due to the metering effect, theforce exerted on the incompressible liquid in chamber 713 is slightlyless than the force exerted upon the front face of plunger 706.Therefore, the spring 142 is not fully compressed and the opposing facesof front piston 140 (i.e., the rear faces of bosses 144) and rear piston14-1 do not meet. The liquid metered through port 147 passes into thecavity 143 between the two pistons and is then released through ports145. As previously mentioned, the fuse assembly, and especially port147, have been designed to produce the desired, predetermined fuse delaytime at this low temperature.

A variance of F. in temperature may cause a considerable change in thepressure of the gas contained in cylinder 704. For example, if the gasis carbon dioxide, a rise in ambient temperature of 100 F. may produce athree-fold increase in gas pressure. With the time delay fuse of FIGURE14, such an increased gas pressure will not affect the fuse delay time,although the force exerted upon the front face of plunger 706 is muchlarger than that exerted at low temperatures.

If, for example, the ambient temperature is at the higher end of thecontemplated temperature range, the force transmitted to front pistonmay be three times the magnitude of the force exerted at lowtemperatures.

which was designed to meter at a low temperature. The

increased force exerted upon rear piston 141 causes a correspondingincrease in the pressure exerted upon the incompressible liquid, whichpressure may be significantly larger than the force exerted upon theliquid at low temperature operation.

As the incompressible liquid is under a greater force, and consequentlyis exerting greater internal pressure, and front piston 140 is likewiseunder a greater force, there is a tendency for pistons 140, 141 to movetogether, i.e., the force exerted upon front piston 140 moving the samerearward and the force exerted by the liquid tending to retard rearwardmovement of rear piston 141 overcome the spring 142 and compress thesame, thereby allowing the rear face of bosses 144 to contact the frontface ofrear piston 141. Such contact of front piston 140 and rear piston141 effectively seals the flow of the incompressible liquid past frontpiston 140. The force exerted upon the incompressible liquid stillcauses metering through port 147 until the pressures in chamber 713 andchamber 148 are approximately equal. When the pressures in the twochambers 713, 148 are approximately equal, spring 142 forces rear piston141 rearward and out of sealing contact with the rear face of bosses144. The liquid contained. within chamber 148 is then free to passthrough ports 145 until the spring is again compressed and the twopistons come into sealing contact, thus again restricting the flow.

Of course, in actual operation the above-described cyclic contact by thefront piston 140 and rear piston 141, with the corresponding sealing ofliquid flow through front piston 140, reaches an equilibrium stagewherein the pistons 140, 141 are maintained in close but not contactingrelationship, i.e. the pistons are at such a distance from one anotherthat they produce a metering effect of the fluid through ports 145without actually stopping the flow therethrough. This equilibriummetering effect is predetermined by the selection of the spring 142 andthe size of port 147, and will operate automatically over a widetemperature range.

Close examination of the time delay fuse of FIGURE 14 will show that,irregardless of the force exerted upon front piston 140, the effectiveforce exerted upon rear piston 141 is that transmitted by the spring142. At low temperatures and pressures, the spring 142 transmits theentire force exerted upon front piston 140 to rear piston 141. At highertemperatures and pressures the spring exerts the same force as at lowertemperatures. The additional force exerted upon front piston 140 iscancelled by the balanced pressure existing between cham-.

bers 713 and 148. In other words, at equilibrium conditions during hightemperature operation, the flow rate of the incompressible liquidthrough port 147 will be approximately the sarne as the flow rate at lowtemperatures, in spite of changes in gas pressure.

FIGURE 15 is a sectional view, showing the front face of rear piston141. As illustrated, port 147 opens into chamber 148 inside of spring142. This port 147 may open into any portion of chamber 148 with twolimitations. First, the port should not be in line with a port 145 inpiston 140. Secondly, the port 147. should not have its liquid flowrestricted by the rear face of boss 144 or by spring 142 when thepistons 140,141 approach or contact each other. Even when pistons 140,141 are in tight contact with one another, port 147 should be so locatedas to freely pass the incompressible fluid into all portions of chamber148.

FIGURE 16 is a sectional view of the rear face of front piston 140;Eight bosses 144 with contained ports 145 are illustrated. Any number ofbosses and ports may be utilized, as long as the crosssectional area ofports 145 12 is appreciably larger than the cross-sectional area of port147.

FIGURE 17 illustrates an embodiment of the .time delay fuse of FIGURE14, and additionally illustrates a modification of the time fuse armingmechanism.

In FIGURE. 17, instead of port 147 passing through the rear piston 141of FIGURE 14, the clearance between rear piston 171 and plunger 706 isso adjusted as to, in effect, produce an annular orifice 177, defined bythe bore of piston 171 and the outer surface of plunger 706. Like-.

wise, instead of a number of ports 145 as shown in FIG- URE 14, theorifice. or port means of front piston may be an annular clearance orgap between front piston 170 and the wall of chamber 713. In such aninstance, chamber 178 between front piston 170 and rear piston 171 mustbe designed to permit fluid pressure to be applied to essentially theentire face of piston 171 when pistons 170, 171 are in sealed contact.

A modified time delay fuse arming means is illustrated in FIGUREl5.Instead of having plunger 706 struck by an extension 212 of frontvalve 206, diaphragm 150 may be employed to cause pointed end 707 ofplunger 706 to puncture area 705 of gas cylinder 704. As illustrated inFIGURE 17, diaphragm 150, which is incontact with plunger 706,-ismounted on the rear grenade case 701. The size of diaphragm 150 is sochosen as'to exert a sufficient force on plunger 706 to puncturecartridge 704 at the predetermined pressure of the gas used to operatethe grenade projecting gun. The diaphragm 150 may be attached to therear of plunger 706 or may be in tight sliding contact with an axialextension 172 of the fuse housing 702. Such a diaphragm arming mechanismis advantageous in that an imperfectly loaded grenade will still beactivated or armed when the grenade is fired from the grenade projectinggun.

The grenade of FIGURE 7 is easily adapted-to operate as a hand-thrownfire extinguishing device. The plunger 706 may be lengthened to extendpast the outer face of plug 712. The base of the grenade can be struckon a hard object to puncture the cylinder 704 and the grenade can thenbe thrown toward the fire.

However, the handle on the grenade shown in FIG- URE 9 is the preferred.modification for arming by hand. This handle mechanism is much lesslikely to cause an accidental arming of the fuse and is easily operatedand reliable.

In FIGURE 9, the grenade 900has the same basic time fuse as FIGURE 7.Handle 901 is molded on to the rear of plug 712. Lever 902 is mounted onhandle 901 by pivot pin 904. Safety pin 903 keeps the lever from movingunless the pin is removed. Extension 905 is so arranged on lever 902that as the lever is moved toward the handle the extension 905 pushesplunger 706 into the grenade and punctures the cartridge 704. Afterpuncturing the cartridge, the gun may beheld in the hand as long asdesired, as long as lever 902 is kept depressed, as extension 905 keepsthe plunger 706 from moving rearward and O-ring 708 seals any gas whichmay be released from cylinder 704 around pointed end 707 of the plunger,When the lever 902 is released the time delay fuse starts in operagon.The grenade may then be thrown by hand toward a As the free flowing fireextinguishing chemical, many various compounds may be used. Dry powders,such as Foray and Purple K, produced by Ansul Chemical Co., are thepreferred compounds. Liquids such as Freon F-1301(bromo-trifiuoromethane produced by Du Pont, may be used. Also, the foamknown to the trade as light water may be utilized as the fireextinguishing chemical. More than one fire extinguishing chemical may beused in the grenade of the present invention. I

Any aiming device such as thoseused on rifles or mortars may be mountedon the fire-fighting gun of this invention. The preferred embodiment isa bubble quadrant calibrated for range indication. However, anyconventional aiming device may be used.

While for fire-fighting purposes the preferred material inside thegrenade is a free flowing fire extinguishing chemical, the scope of thisinvention covers any material which is adapted to be projected in agrenade or canister. Included among such materials, for'example, arecarbon tetrachloride, tear gas, explosives, napalms, smoke-producingcompounds, marking powders, insecticides, and various plant killingcompounds. The grenade may readily be modified to carry an attached lifeline, and the compressed gas in the grenade may be used to inflate alife ring when at the desired target.

Although the balanced spool valve is the preferred valve system fortriggering operations, obviously a number of modifications could bemade. Separate air inlet and outlet ports with two or more separatevalves could be used, for example. In such cases it is preferred, butnot essential, that the valves be quick-opening.

The stock assembly may be attached to the gun at areas other than therear housing. The auxiliary chamber 221 may be eliminated with theconsequent elimination of most of rear housing 218 if the stock assemblyis attached to another point on the gun. While the safety lock assemblyis desirable, it is not necessary for operation of the gun.

I claim:

1. A fire extinguishing grenade-projecting device for arming andprojecting a fire extinguishing grenade by means of compressed fluid,said device comprising means for holding a fire extinguishing grenade,valve means operated by fluid pressure acting on differential pistonareas to release compressed fluid and direct the compressed fluid intosaid means for holding a fire extinguishing grenade, said valve means inassociated relationship with arming means, said arming means adapted todeliver a blow to the base of a grenade contained within said means forholding a fire extinguishing grenade, whereby a grenade contained withinthe means for containing a fire extinguishing grenade is armed andprojected from the gun upon operation of said valve means.

2. A fire extinguishing grenade-projecting device as claimed in claim 1,comprising, a rear and a front pressure chamber, a rear valve seating inthe rear of said rear pressure chamber and a front valve seating in thefront of said front pressure chamber, said valves connected by a valvestem and said rear valve of larger surface area exposed to internalfluid pressure than said front valve, said pressure chambers connectedby a port containing a one-way flow regulating device permitting fluidflow only from said rear pressure chamber to said front pressurechamber, a valve system for controlling the flow of fluid to and fromsaid rear pressure chamber, a barrel adapted to hold and guide a fireextinguishing grenade mounted in front of said front valve, and aprojection on said front valve adapted to strike the rear face of agrenade contained in said barrel when said front valve is unseated.

3. The device of claim 2 wherein said valve system for controlling theflow of fluid to and from said rear pressure chamber is a balanced spoolvalve.

4. The device of claim 2 wherein a multiplicity of barrels are attachedto the front end of the front pressure chamber, rotating means areattached to the front receiver and the multiplicity of barrels arerotated by the rotating means in front of the front pressure chamber andfront valve whereby grenades contained in each barrel may be fired fromthe gun in turn.

5. The device of claim 4, wherein said rotating means comprises apiston, a connecting rod, a ratchet and a gas port connecting the frontpressure chamber with the face of the piston, whereby gas pressure inthe front pressure chamber exerts a force on the piston, the pistondriving the connecting rod, the connecting rod rotating the ratchet, theratchet connected to the multiplicity of barrels and rotating thebarrels.

6. In a device for projecting fire extinguishing grenades as claimed inclaim 1, the combination of a front pressure chamber and a rear pressurechamber, the chambers in line, a wall separating the chambers, a portdefined by the wall and running through the wall, a one-way flowregulating device located in the port and permitting fluid flow onlyfrom the rear pressure chamber to the front pressure chamber, a rearvalve seating at the rearmost end of the rear pressure chamber, a frontvalve seating at the front end of the front pressure chamber, the frontvalve having a smaller surface area exposed to the interior of the frontpressure chamber than the rear valve has exposed to the interior of therear pressure chamber, a valve stem connecting the front valve and therear valve and passing through the wall, compressed gas supply means forsupplying gas to the rear pressure chamber, valve means for controllingthe flow of gas into and out of the rear pressure chamber, a barrelattached to the front end of the front pressure chamber and adapted tocontain grenades and to receive the flow of gas when a ditferentialpressure in the front and rear pressure chambers, acting on differentialvalve surface areas, operates the valves.

7. The device of claim 6 wherein said valve means is a balanced spoolvalve.

8. The device of claim 6 wherein a multiplicity of barrels are attachedto the front end of the front pressure chamber, rotating means areattached to the front receiver and the multiplicity of barrels arerotated by the rotating means in front of the front pressure chamber andfront valve whereby grenades contained in each barrel may be fired fromthe gun in turn.

9. The device of claim 8, wherein said rotating means comprises apiston, a connecting rod, a ratchet and a gas port connecting the frontpressure chamber with the face of the piston, whereby gas pressure inthe front pressure chamber exerts a force on the piston, the pistondriving the connecting rod, the connecting rod rotating the ratchet, theratchet connected to the multiplicity of barrels and rotating thebarrels.

10. A fire extinguishing grenade consisting of a grenade case filledwith free flowing fire extinguishing chemicals, a compressed gascylinder, and a time fuse assembly means which is armed by a blowdelivered to the rear of the grenade case and is operated bycompressedgas from the cylinder, whereby compressed gas from the compressed gascylinder is released to the interior of the grenade case, therebyrupturing the case, at a predetermined time.

11. The grenade of claim 10, wherein the gas cylinder is attached to thetime fuse assembly means, a plunger is contained within the time fuseassembly means, and the gas cylinder is punctured by the plunger whenthe plunger is struck.

12. The grenade of claim 11 wherein the time fuse assembly meansconsists of a plunger mounted in a bore defined by the time fuseassembly means, a compressed gas cylinder mounted at the inner end ofthe bore defined by the time fuse assembly means, sealing means on theplunger, a piston located on the plunger, a chamber defined by the timefuse assembly and containing a liquid and the piston, a shoulder on theplunger to engage the piston and move the piston rearward when theplunger moves rearward, a small port extending through the piston formetering the liquid, and gas escape ports leading from the chamber tothe inside of the grenade case.

13. The grenade of claim 12 wherein fuse time adjusting means aremounted on the plunger.

14. The grenade of claim 11 wherein said time fuse assembly consists ofsaid plunger mounted in a bore, said gas cylinder mounted at the innerend of said bore, a first port connecting said bore to a first pressurechamber, a second pressure chamber immediately to the rear of said firstpressure chamber and separated from said first pressure chamber by afirst piston, a second port in said first piston connecting saidpressure chambers, a third port connecting said first pressure chamberwith the interior 1 5 of said grenade case, a second piston arranged insaid third port to seal the same before arming, a stem connecting saidpistons, said second piston being of smaller area than said firstpiston.

15. The grenade of claim 12 wherein said time fuse assembly is operatedby the metering of a fluid through a small port, said fluid being forcedthrough the port by gas pressure from the cylinder.

16. The grenade of claim 12 wherein said time fuse asserhbly is operatedby differential piston areas exposed to compressed gas from saidcylinder, which releases said compressed gas to the inside of saidgrenade case after a predetermined time.

References Cited UNITED STATES PATENTS Malcolm 124-11 Woodberry 102-82Smith 102-82 Pearson et a1. 169-36 Talbot 169-36 Englis 124-11 Frevel124-11 EVERETT W. K1RBY,'Primary Examiner.

1. A FIRE EXTINGUISHING GRENADE-PROJECTING DEVICE FOR ARMING ANDPROJECTING A FIRE EXTINGUISHING GRENADE BY MEANS OF COMPRESSED FLUID,SAID DEVICE COMPRISING MEANS FOR HOLDING A FIRE EXTINGUISHING GRENADE,VALVE MEANS OPERATED BY FLUID PRESSURE ACTING ON DIFFERENTIAL PISTONAREAS TO RELEASE COMPRESSED FLUID AND DIRECT THE COMPRESSED FLUID INTOSAID MEANS FOR HOLDING A FIRE EXTINGUISHING GRENADE, SAID VALVE MEANS INASSOCIATED RELATIONSHIP WITH ARMING MEANS, SAID ARMING MEANS ADAPTED TODELIVER A BLOW TO THE BASE OF A GRENADE CONTAINED WITHIN SAID MEANS FORHOLDING A FIRE EXTINGUISHING GRENADE, WHEREBY A GRENADE CONTAINED WITHINTHE MEANS FOR CONTAINING A FIRE EXTINGUISHING GRENADE IS ARMED ANDPROTECTED FROM THE GUN UPON OPERATION OF SAID VALVE MEANS.